Aluminum copper induction brazing

Copper aluminum flux cored welding wire is a brazing material that can weld copper and aluminum together through brazing process, hence the name copper aluminum welding wire (named according to its purpose). This welding wire is a new type of material that has been widely used in industry. There are currently no relevant standards at home and abroad that specify its material composition and specifications.

Due to the fact that the price of copper is more than three times that of aluminum, many manufacturers are using technological changes to replace the parts of the workpiece that can be replaced with aluminum with aluminum, while the irreplaceable parts still use copper. This requires welding the two materials together, and copper aluminum welding wire can precisely solve the problem of welding these two materials.

Copper aluminum flux cored welding wire is a composite brazing material consisting of a zinc aluminum alloy outer layer and a white fluoride flux inner layer. The white flux is non hygroscopic, non corrosive, and does not require cleaning after welding. At present, it is mainly used for flame brazing of copper and aluminum alloys, brass and aluminum alloys, aluminum alloys and aluminum alloys, high-frequency induction brazing, and furnace brazing.

Copper and aluminum are welded together using copper and aluminum welding wires from Rukos, USA, through flame brazing, furnace brazing, and high-frequency brazing. The brazing process uses the brazing material as an intermediate medium to weld copper and aluminum together (in fact, a metallurgical reaction occurs, and the brazing material infiltrates into the molecular structure of copper and aluminum through capillary action). After welding, the joint is well formed, with good tensile and shear properties, conductivity, and corrosion resistance, making it a commonly used copper aluminum welding method.

1. Suitable base material for welding

Copper: Purple copper, brass.

Aluminum and aluminum alloys: 1xxx; 2xxx; 3 xxxx; 4xxxxx; A series of materials such as 6A (American Aluminum Association AA standard).

2. Welding tools: ordinary welding torch, rubber hose

Gas source: liquefied petroleum gas+oxygen; Or acetylene+oxygen; Or propane+oxygen.

Aluminum copper flux cored welding wire is divided into low-temperature flux cored welding wire 9802 and high-temperature flux cored welding wire 7822.

Ingredients: AL, Zn;

Solder flux mass fraction: 18-22%;

Welding wire diameter mm: Φ 2.0; Packaging (kg/tray): 5.0;

Brazing temperature (℃): 385-450-485;

Applicable base materials: Welding of aluminum and copper pipes in the refrigeration industry;

Performance characteristics: Low temperature brazing, moderate fluidity (able to stack copper aluminum pipe joints), tensile and shear strength, good conductivity, non corrosive self brazing seamless welding wire, good welding without leakage.

3. According to the different products used, welding methods can be divided into two types:

(1) Copper aluminum flux cored welding wire

Thoroughly remove oil stains, dirt, insulation layer, etc. from the base material before welding, move the welding gun back and forth to evenly heat the welding area, first heat the thick parts, and then heat the thin parts; Heat the copper parts first, and then heat the aluminum parts; When the temperature of the welded part reaches 450-500 ° C, add the welding wire to the welding area to allow the welding wire to melt evenly and flow into the weld seam (flames cannot be directly aimed at the welding wire for heating). Then use a flame to gently scan the welding area to ensure that the brazing material is spread and positioned. Remove the welding gun and let it cool naturally to complete the welding.

(2) Combination of brazing flux paste and brazing wire

Before welding, thoroughly remove the oil, dirt, insulation layer, etc. of the base material. Use a brush or other tools to evenly apply brazing paste to the welding area, close the copper aluminum base material, maintain the flatness of the welded part, fix it with appropriate fixtures, heat the thick part with flame first, and then heat the thin part; Heat the copper parts first, and then heat the aluminum parts to ensure uniform heating of the welded parts. When heating, it can be seen from the weld seam that the brazing paste first changes from a paste like state to a white solid, and then continues to be heated. When the solid changes to a liquid state, the brazing paste reaches the active temperature, and the brazing wire is added to the weld seam in a timely manner. When the weld seam is filled with brazing material, a flame is used to slightly sweep the welding area, so that the residual brazing flux can be discharged from the weld seam and avoid slag inclusion. Remove the welding gun and wait for the workpiece to cool naturally to complete the welding.

4. Application industry

1. Used for welding aluminum wires and copper joints, copper bars and aluminum foils in transformers and reactors (aluminum wires can replace copper wires in transformer coils, but aluminum joints cannot replace copper joints);

2. Used for welding aluminum and copper pipes in condensers, evaporators, and radiators in refrigerators and air conditioners;

3. Welding of copper and aluminum wires in products such as motors, batteries, and household appliances.

With the maturity of technology, copper aluminum welding wires will be widely used in various industries.